The invention is directed to a method for producing a luminophore layer.
DE 195 16 450 C1 discloses a method for producing a luminiferous layer composed of CsI:Tl. It is thereby provided that the pressure in the vapor-deposition system is higher than the vapor pressure of the thallium iodide, at least during the vapor-deposition. A luminophore layer whose light yield is improved can be produced based on this method.
An experimental method for producing a luminophore layer composed of CsI(Na) is also known from “preparation of Self-Supporting Large-Area Polycrystalline Structures of CsI(Na) by Evaporation”, W. Schubert, Siemens Forsch.- und Entwickl.-Ber., Vol. 3 (1974), No. 2, Springer Verlag, 1974. A vapor-deposition rate of 65 weight-% of the utilized material is thereby achieved.
DE 198 52 326 A1 discloses a method that is particularly suited for coating a substrate with GaBr-doped luminophores. The luminophore is thereby placed onto a heated evaporation source in a vacuum in the vapor-deposition chamber, said luminophore immediately vaporizing thereat and depositing on the substrate.
DE 44 29 013 A1 discloses an apparatus for the vapor-deposition of a substrate having an X-ray measuring instrument for measuring the layer thickness. The vapor-deposition rate is regulated dependent on the measured result of the layer thickness measurement in order to achieve an optimally uniform layer thickness.
DE 24 35 629 A1 discloses a method for smoothing the surface of a luminophore layer applied on a substrate. The surface is thereby worked with forging bodies in the fashion of forging.
DE 28 32 141 A1 discloses a method for manufacturing radiation converter screens, whereby a luminophore layer applied on a substrate is ground and polished for achieving a uniform layer thickness. Irregularities that project above the luminophore layer are thereby in fact eliminated. However, relatively long-wave irregularities are generated when grinding and polishing. Moreover, relatively large grinding agent grains are worked into the luminophore layer during grinding. These reduce the optical quality of the luminophore layer.
In order to counter this disadvantage, attempts have already been made in the Prior Art to arrange the luminophore source at as great a distance as possible from the substrate during the vapor-deposition. Luminophore layers deposited in this way are relatively uniform in terms of their layer thickness. However, a great deal of material must be utilized here during the vapor-deposition because only about 10 weight-% of the evaporated material are deposited on the substrate here.